Conventionally, in the case where characters and graphics are developed on a screen, two-dimensional position information as base data is occasionally inputted into a processor system such as a personal computer, an electronic pocket notebook and a portable terminal. As a tool which can input such two-dimensional position information as data, a mouse or a tablet is generally used.
Meanwhile, three-dimensional graphics, conducting of a musical performance, etc. using a processor system require a spatial position information. For example, in the case of the conducting of a musical performance, movement of a baton by a conductor should be recognized, and thus three-dimensional position information corresponding to a spatial position of the baton is inputted as data. As an example of such a technique, Japanese Unexamined Patent Publication No. 3-210622/1991 (Tokukaihei 3-210622) discloses a three-dimensional position data input method using light and supersonic waves for recognizing a three-dimensional position of the baton.
The above three-dimensional position data input method uses a baton as an input device. The baton is provided with a luminescent element at one end and a supersonic wave generator, which synchronizes with turning on and off of the luminescent element so as to generate supersonic waves intermittently, adjacently to the luminescent element. Moreover, a detecting unit is provided with three supersonic wave sensors and one light receiving element.
In such an arrangement, respective distances between the baton and the three supersonic wave sensors are calculated by a time difference between time at which a light is received from the luminescent element and time at which the three supersonic wave sensors receive supersonic waves. Therefore, the point position of the baton can be obtained by obtaining a coordinate of the intersection of three spherical surfaces whose radiuses are respectively the above three distances.
However, in the case where the data are directly inputted into an output unit adopting the two-dimensional position data input method by the three-dimensional position data input method, only two-dimensional coordinate information can be used for conversion from three dimension into two-dimension. For this reason, lack of information for one dimension occurs.
In addition, if data are inputted from a plurality of input units, the detecting unit can detect these data respectively, but the output unit adopting a two-dimensional position data input method cannot display plural pieces of position information indicated by the input units as different position information. Namely, plural pieces of three-dimensional position information obtained from a plurality of input units can be displayed on the two-dimensional screen as information, but the operator cannot judge which input unit outputs one piece of three-dimensional position information.